Soaring Guidance
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
000
UXUS97 KPUB 161206
SRGPUB
Soaring Forecast
National Weather Service Pueblo, Colorado
0606 MDT Tuesday, April 16, 2024
This forecast is for the Air Force Academy for Tuesday, April 16, 2024:
If the trigger temperature of 45.2 F/7.4 C is reached...then
Thermal Soaring Index....................... Good
Maximum rate of lift........................ 1570 ft/min (8.0 m/s)
Maximum height of thermals.................. 24391 ft MSL (16732 ft AGL)
Forecast maximum temperature................... 65.0 F/18.8 C
Time of trigger temperature.................... 0830 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... None
Surface winds during soaring window............ Between 20 mph and 30 mph
Height of the -3 thermal index................. 19736 ft MSL (12077 ft AGL)
Thermal soaring outlook for Wednesday 04/17.... Excellent
Wave Soaring Index............................. Not available
Remarks... Early morning clouds/showers will quickly dissipate by mid morning
with clear skies thereafter.
Sunrise/Sunset.................... 06:19:58 / 19:37:49 MDT
Total possible sunshine........... 13 hr 17 min 51 sec (797 min 51 sec)
Altitude of sun at 12:58:53 MDT... 61.52 degrees
Upper air data from numerical model forecast valid on 04/16/2024 at 0600 MDT
Freezing level.................. 8627 ft MSL (968 ft AGL)
Convective condensation level... 11957 ft MSL (4298 ft AGL)
Lifted condensation level....... 16406 ft MSL (8747 ft AGL)
Lifted index.................... -6.3
K index......................... +18.2
Height Temperature Wind Wind Spd Lapse Rate ConvectionT Thermal Lift Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft deg C deg F Index fpm m/s
--------------------------------------------------------------------------------
50000 -53.4 -64.1 255 35 18 1.5 0.8 M M M M M
45000 -51.2 -60.2 265 39 20 1.6 0.9 M M M M M
40000 -48.6 -55.5 275 39 20 1.7 0.9 M M M M M
38000 -47.7 -53.9 280 37 19 1.3 0.7 M M M M M
36000 -46.8 -52.2 280 33 17 1.3 0.7 M M M M M
34000 -46.1 -51.0 285 29 15 -0.2 -0.1 M M M M M
32000 -46.5 -51.7 335 37 19 -0.6 -0.3 M M M M M
30000 -46.7 -52.1 355 58 30 5.6 3.1 21.6 70.8 2.5 M M
29000 -44.1 -47.4 350 59 30 8.7 4.8 21.0 69.9 2.1 M M
28000 -41.5 -42.7 345 59 30 8.8 4.8 20.6 69.1 1.8 M M
27000 -38.9 -38.0 345 60 31 8.8 4.8 20.4 68.7 1.6 M M
26000 -36.4 -33.5 340 59 30 7.7 4.2 19.7 67.5 1.1 M M
25000 -34.2 -29.6 340 57 29 7.6 4.2 18.9 66.0 0.4 M M
24000 -31.9 -25.4 335 54 28 7.7 4.2 18.2 64.8 -0.2 1542 7.8
23000 -29.0 -20.2 335 52 27 7.9 4.3 17.3 63.1 -0.9 1418 7.2
22000 -26.7 -16.1 335 50 26 7.9 4.3 16.6 61.9 -1.5 1319 6.7
21000 -24.3 -11.7 335 48 25 7.8 4.3 16.0 60.9 -2.1 1219 6.2
20000 -22.1 -7.8 335 44 23 7.5 4.1 15.2 59.4 -2.8 1123 5.7
19500 -21.0 -5.8 335 42 22 7.5 4.1 14.8 58.7 -3.2 1075 5.5
19000 -19.9 -3.8 335 40 21 7.5 4.1 14.5 58.0 -3.6 1027 5.2
18500 -18.8 -1.8 335 38 19 7.6 4.2 14.1 57.4 -3.9 979 5.0
18000 -17.7 0.1 335 35 18 7.0 3.8 13.7 56.7 -4.3 932 4.7
17500 -16.7 1.9 330 33 17 7.0 3.9 13.3 55.9 -4.8 886 4.5
17000 -15.6 3.9 330 30 15 6.9 3.8 12.8 55.1 -5.2 840 4.3
16500 -14.6 5.7 330 28 15 6.9 3.8 12.3 54.2 -5.7 795 4.0
16000 -13.6 7.5 330 27 14 6.9 3.8 11.8 53.3 -6.2 750 3.8
15500 -12.6 9.3 330 26 13 7.1 3.9 11.4 52.5 -6.6 704 3.6
15000 -11.5 11.3 330 25 13 7.2 3.9 11.0 51.7 -7.1 659 3.3
14500 -10.5 13.1 335 26 13 6.5 3.6 10.5 50.9 -7.6 614 3.1
14000 -9.6 14.7 335 27 14 6.5 3.6 10.0 50.0 -8.2 571 2.9
13500 -8.6 16.5 335 30 15 8.0 4.4 9.6 49.2 -8.7 526 2.7
13000 -7.5 18.5 335 33 17 9.8 5.4 9.3 48.7 -9.0 477 2.4
12500 -7.0 19.4 335 38 19 1.8 1.0 8.3 46.9 -10.1 449 2.3
12000 -5.8 21.6 330 41 21 6.9 3.8 8.0 46.4 -10.4 399 2.0
11750 -5.2 22.6 330 42 22 10.8 5.9 7.8 46.1 -10.6 374 1.9
11500 -4.3 24.3 330 44 23 10.3 5.7 8.0 46.5 -10.5 340 1.7
11250 -3.8 25.2 325 46 23 5.5 3.0 7.8 46.1 -10.7 317 1.6
11000 -3.4 25.9 325 47 24 5.5 3.0 7.5 45.5 -11.1 298 1.5
10750 -3.0 26.6 325 49 25 5.6 3.0 7.2 44.9 -11.4 278 1.4
10500 -2.6 27.3 320 51 26 6.1 3.3 6.9 44.4 -11.8 258 1.3
10250 -2.2 28.0 320 54 28 5.6 3.1 6.6 43.8 -12.1 238 1.2
10000 -1.8 28.8 315 54 28 5.0 2.7 6.2 43.2 -12.5 219 1.1
9750 -1.4 29.5 315 54 28 4.9 2.7 5.9 42.5 -12.9 201 1.0
9500 -0.8 30.6 310 52 27 3.5 1.9 5.0 41.0 -13.8 168 0.9
9250 -0.6 30.9 305 49 25 2.3 1.3 4.5 40.1 -14.4 155 0.8
9000 -0.5 31.1 305 47 24 3.9 2.1 3.9 39.1 -14.9 142 0.7
8750 -0.0 32.0 300 44 23 6.9 3.8 3.6 38.6 -15.3 122 0.6
8500 0.5 32.9 300 41 21 7.3 4.0 3.5 38.2 -15.5 99 0.5
8250 1.0 33.8 295 37 19 6.7 3.7 3.3 37.9 -15.8 76 0.4
8000 1.5 34.7 295 33 17 6.4 3.5 3.0 37.4 -16.1 54 0.3
7750 2.1 35.8 295 21 11 9.5 5.2 2.8 37.1 -16.3 30 0.2
7500 M M M M M M M M M M M M
7250 M M M M M M M M M M M M
7000 M M M M M M M M M M M M
6750 M M M M M M M M M M M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
04/16/2024 at 0900 MDT | 04/16/2024 at 1200 MDT
|
CAPE... 0.0 LI... +1.9 | CAPE... +0.5 LI... +2.6
CINH... 0.0 K Index... +16.3 | CINH... 0.0 K Index... +4.1
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
50000 -54.4 -65.9 265 33 17 1.5 0.8 | -55.2 -67.4 255 36 18 1.6 0.9
45000 -52.1 -61.8 275 45 23 1.9 1.0 | -52.8 -63.0 260 41 21 1.2 0.6
40000 -49.2 -56.6 275 36 19 1.9 1.1 | -51.2 -60.2 260 34 18 1.1 0.6
38000 -48.8 -55.8 280 36 18 -1.0 -0.5 | -51.3 -60.3 265 32 17 -1.7 -0.9
36000 -49.5 -57.1 290 39 20 -1.0 -0.5 | -52.4 -62.3 280 32 16 -1.7 -0.9
34000 -49.8 -57.6 295 41 21 2.9 1.6 | -52.7 -62.9 295 33 17 6.0 3.3
32000 -48.3 -54.9 315 39 20 2.5 1.4 | -49.3 -56.7 305 29 15 5.6 3.0
30000 -46.3 -51.3 335 42 22 9.8 5.4 | -45.6 -50.1 310 26 13 9.3 5.1
29000 -43.6 -46.5 335 42 21 9.0 4.9 | -42.8 -45.0 305 25 13 9.2 5.0
28000 -40.9 -41.6 335 41 21 9.0 4.9 | -40.1 -40.2 300 25 13 9.2 5.0
27000 -38.3 -36.9 335 40 21 9.0 4.9 | -37.3 -35.1 295 25 13 9.2 5.0
26000 -35.6 -32.1 335 43 22 9.0 5.0 | -34.6 -30.3 295 26 13 9.1 5.0
25000 -32.9 -27.2 340 46 24 9.0 5.0 | -31.9 -25.4 295 27 14 9.1 5.0
24000 -30.2 -22.4 340 49 25 9.1 5.0 | -29.2 -20.6 295 29 15 9.1 5.0
23000 -27.7 -17.9 340 51 27 8.0 4.4 | -25.9 -14.6 295 29 15 8.8 4.8
22000 -25.3 -13.5 340 53 27 8.0 4.4 | -23.2 -9.8 300 30 15 8.8 4.8
21000 -22.3 -8.1 340 56 29 7.6 4.2 | -20.6 -5.1 300 30 16 7.3 4.0
20000 -20.1 -4.2 340 56 29 7.4 4.1 | -18.5 -1.3 310 30 16 7.2 3.9
19500 -19.0 -2.2 340 56 29 7.4 4.1 | -17.5 0.5 315 31 16 7.2 3.9
19000 -17.9 -0.2 340 57 29 7.4 4.1 | -16.4 2.5 315 31 16 7.2 3.9
18500 -16.8 1.8 340 57 29 7.2 3.9 | -15.4 4.3 320 32 16 6.1 3.4
18000 -15.8 3.6 340 57 29 6.7 3.7 | -14.6 5.7 325 34 17 5.5 3.0
17500 -14.8 5.4 340 57 29 6.7 3.7 | -13.8 7.2 325 36 19 5.5 3.0
17000 -13.8 7.2 340 57 29 6.6 3.6 | -12.9 8.8 330 38 20 5.6 3.1
16500 -12.8 9.0 340 56 29 6.6 3.6 | -12.1 10.2 330 40 20 5.6 3.0
16000 -11.9 10.6 340 56 29 6.2 3.4 | -11.3 11.7 330 41 21 5.8 3.2
15500 -11.0 12.2 340 56 29 6.0 3.3 | -10.4 13.3 330 42 22 5.9 3.2
15000 -10.1 13.8 340 56 29 5.9 3.2 | -9.6 14.7 335 43 22 6.3 3.5
14500 -9.3 15.3 340 57 29 5.5 3.0 | -8.6 16.5 335 44 22 6.8 3.7
14000 -8.5 16.7 340 58 30 5.5 3.0 | -7.6 18.3 335 44 23 6.8 3.7
13500 -7.6 18.3 340 59 30 6.9 3.8 | -6.7 19.9 335 44 23 6.8 3.7
13000 -6.6 20.1 340 59 30 6.1 3.4 | -5.7 21.7 330 44 23 10.4 5.7
12500 -5.3 22.5 340 59 30 9.6 5.3 | -4.3 24.3 330 43 22 5.6 3.1
12000 -4.3 24.3 340 58 30 6.8 3.7 | -3.4 25.9 330 43 22 6.3 3.5
11750 -3.9 25.0 340 58 30 6.4 3.5 | -2.9 26.8 325 42 22 8.0 4.4
11500 -3.4 25.9 335 56 29 7.1 3.9 | -2.3 27.9 325 41 21 9.3 5.1
11250 -2.8 27.0 335 56 29 7.7 4.2 | -1.6 29.1 325 39 20 9.0 4.9
11000 -2.3 27.9 335 55 28 7.7 4.2 | -0.9 30.4 325 38 19 9.0 5.0
10750 -1.7 28.9 335 54 28 7.3 4.0 | -0.2 31.6 325 36 19 9.7 5.3
10500 -1.2 29.8 330 53 27 6.7 3.7 | 0.5 32.9 325 35 18 10.2 5.6
10250 -0.6 30.9 330 52 27 7.9 4.3 | 1.2 34.2 325 34 18 9.6 5.3
10000 0.0 32.0 325 50 26 9.1 5.0 | 1.9 35.4 325 34 17 9.4 5.1
9750 0.7 33.3 325 49 25 7.5 4.1 | 2.7 36.9 325 33 17 10.0 5.5
9500 1.1 34.0 325 48 25 5.9 3.2 | 3.4 38.1 325 33 17 10.3 5.7
9250 1.6 34.9 320 46 24 7.1 3.9 | 4.2 39.6 325 33 17 10.6 5.8
9000 2.2 36.0 320 44 22 8.7 4.8 | 5.0 41.0 325 32 17 11.1 6.1
8750 2.8 37.0 320 41 21 7.6 4.1 | 5.8 42.4 325 32 16 10.8 5.9
8500 3.3 37.9 320 38 19 6.5 3.5 | 6.6 43.9 325 31 16 11.3 6.2
8250 3.8 38.8 315 34 18 6.4 3.5 | 8.1 46.6 325 30 15 14.1 7.7
8000 4.2 39.6 315 31 16 8.2 4.5 | 9.8 49.6 325 26 14 31.8 17.5
7750 5.0 41.0 315 25 13 14.0 7.7 | 12.0 53.6 330 22 11 15.0 8.2
7500 M M M M M M M | M M M M M M M
7250 M M M M M M M | M M M M M M M
7000 M M M M M M M | M M M M M M M
6750 M M M M M M M | M M M M M M M
04/16/2024 at 1500 MDT | 04/16/2024 at 1800 MDT
|
CAPE... +37.3 LI... +1.5 | CAPE... +49.2 LI... +0.9
CINH... -23.6 K Index... +5.0 | CINH... -29.4 K Index... +2.6
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
50000 -55.8 -68.4 260 40 21 1.7 1.3 | -56.4 -69.5 250 42 22 2.6 1.4
45000 -53.2 -63.8 260 49 25 1.4 0.7 | -52.7 -62.9 260 47 24 1.2 0.7
40000 -51.2 -60.2 260 44 23 1.3 0.7 | -50.9 -59.6 265 39 20 1.1 0.6
38000 -51.4 -60.5 260 39 20 -1.6 -0.9 | -51.4 -60.5 270 36 19 -2.1 -1.2
36000 -52.4 -62.3 260 32 17 -1.6 -0.9 | -52.6 -62.7 280 35 18 -2.1 -1.2
34000 -52.5 -62.5 265 27 14 6.0 3.3 | -52.9 -63.2 285 35 18 6.2 3.4
32000 -49.1 -56.4 280 30 15 5.7 3.1 | -49.3 -56.7 290 35 18 6.1 3.3
30000 -45.3 -49.5 285 34 17 8.6 4.7 | -45.3 -49.5 295 36 19 8.1 4.5
29000 -42.7 -44.9 285 35 18 8.6 4.7 | -42.9 -45.2 295 37 19 8.1 4.5
28000 -40.2 -40.4 285 36 19 8.6 4.7 | -40.4 -40.7 295 37 19 8.2 4.5
27000 -37.6 -35.7 280 38 20 8.7 4.8 | -38.0 -36.4 290 38 19 8.4 4.6
26000 -35.0 -31.0 280 39 20 8.9 4.9 | -35.4 -31.7 290 37 19 8.6 4.7
25000 -32.3 -26.1 285 39 20 8.9 4.9 | -32.9 -27.2 290 37 19 8.6 4.7
24000 -29.6 -21.3 285 40 21 8.8 4.8 | -30.3 -22.5 285 36 19 8.6 4.7
23000 -26.5 -15.7 285 37 19 8.2 4.5 | -27.1 -16.8 285 34 18 8.6 4.7
22000 -24.1 -11.4 285 34 18 8.2 4.5 | -24.5 -12.1 290 32 17 8.6 4.7
21000 -21.6 -6.9 285 32 16 8.6 4.7 | -21.9 -7.4 290 31 16 8.5 4.7
20000 -19.0 -2.2 285 29 15 8.6 4.7 | -19.4 -2.9 285 30 15 8.5 4.7
19500 -17.7 0.1 280 28 15 8.6 4.7 | -18.1 -0.6 285 30 15 8.5 4.7
19000 -16.5 2.3 280 27 14 8.6 4.7 | -16.8 1.8 285 29 15 8.5 4.7
18500 -15.2 4.6 280 26 13 7.3 4.0 | -15.5 4.1 280 29 15 8.6 4.7
18000 -14.2 6.4 280 25 13 7.0 3.8 | -14.3 6.3 280 28 14 8.5 4.7
17500 -13.2 8.2 280 24 12 6.7 3.7 | -13.0 8.6 275 27 14 7.2 4.0
17000 -12.3 9.9 285 23 12 5.2 2.8 | -12.2 10.0 275 26 13 5.0 2.7
16500 -11.6 11.1 285 23 12 5.3 2.9 | -11.5 11.3 270 25 13 5.2 2.9
16000 -10.9 12.4 290 23 12 4.7 2.6 | -10.9 12.4 275 23 12 4.0 2.2
15500 -10.2 13.6 300 25 13 4.8 2.6 | -10.3 13.5 280 21 11 4.1 2.3
15000 -9.5 14.9 305 27 14 5.5 3.0 | -9.6 14.7 285 20 10 7.7 4.2
14500 -8.7 16.3 305 28 14 5.9 3.3 | -8.4 16.9 285 19 10 8.5 4.6
14000 -7.9 17.8 305 30 15 7.1 3.9 | -7.2 19.0 290 19 10 8.9 4.9
13500 -6.7 19.9 305 29 15 9.2 5.0 | -5.8 21.6 290 19 10 9.5 5.2
13000 -5.4 22.3 310 28 14 12.4 6.8 | -4.4 24.1 290 18 9 12.9 7.1
12500 -3.7 25.3 310 27 14 7.4 4.1 | -2.7 27.1 295 18 9 7.2 3.9
12000 -2.4 27.7 315 25 13 8.6 4.7 | -1.5 29.3 295 18 9 8.8 4.8
11750 -1.7 28.9 315 25 13 10.3 5.6 | -0.8 30.6 295 17 9 10.7 5.8
11500 -1.0 30.2 315 25 13 10.0 5.5 | 0.0 32.0 300 17 9 10.0 5.5
11250 -0.3 31.5 315 25 13 9.0 5.0 | 0.7 33.3 300 17 9 9.2 5.0
11000 0.4 32.7 320 24 13 9.4 5.1 | 1.4 34.5 305 17 9 9.3 5.1
10750 1.1 34.0 320 24 13 9.6 5.3 | 2.1 35.8 305 16 8 9.1 5.0
10500 1.9 35.4 320 24 12 9.8 5.4 | 2.8 37.0 310 16 8 9.2 5.1
10250 2.6 36.7 320 24 12 10.5 5.8 | 3.5 38.3 310 16 8 10.7 5.9
10000 3.4 38.1 320 24 12 10.6 5.8 | 4.3 39.7 310 16 8 10.9 6.0
9750 4.2 39.6 320 24 12 9.9 5.4 | 5.1 41.2 310 16 8 9.8 5.4
9500 4.9 40.8 320 24 12 9.5 5.2 | 5.8 42.4 315 16 8 10.0 5.5
9250 5.6 42.1 320 23 12 10.0 5.5 | 6.6 43.9 315 16 8 9.3 5.1
9000 6.4 43.5 320 23 12 10.8 5.9 | 7.2 45.0 315 16 8 9.4 5.2
8750 7.2 45.0 325 23 12 10.7 5.9 | 8.0 46.4 315 15 8 10.3 5.7
8500 8.0 46.4 325 23 12 11.5 6.3 | 8.8 47.8 315 15 8 10.4 5.7
8250 9.5 49.1 325 22 11 14.8 8.1 | 9.5 49.1 320 15 8 9.7 5.3
8000 11.4 52.5 325 20 10 35.3 19.4 | 11.4 52.5 320 13 7 18.1 10.0
7750 13.3 55.9 325 18 9 -0.2 -0.1 | 12.5 54.5 325 12 6 6.8 3.7
7500 M M M M M M M | M M M M M M M
7250 M M M M M M M | M M M M M M M
7000 M M M M M M M | M M M M M M M
6750 M M M M M M M | M M M M M M M
________________________________________________________________________________
This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 UTC). It is not continuously monitored nor updated after its initial
issuance.
The information contained herein is based on rawinsonde observation and/or
numerical weather prediction model data taken near the Air Force Academy
in Colorado Springs, Colorado at
North Latitude: 38 deg 58 min 48.000 sec
West Longitude: 104 deg 49 min 12.000 sec
Elevation: 6572 feet (2003 meters)
and may not be representative of other areas along the Front Range of the
Colorado Rocky Mountains. Note that some elevations in numerical weather
prediction models differ from actual station elevations, which can lead to
data which appear to be below ground. Erroneous data such as these should
not be used.
The content and format of this report as well as the issuance times are subject
to change without prior notice. Comments and suggestions are welcome and should
be directed to one of the addresses or phone numbers shown at the bottom of this
page. To expedite a response to comments, be sure to mention your interest in
the soaring forecast.
DEFINITIONS:
CAPE (Convective Available Potential Energy) - An integrated measure of the
energy available for convective development, also known as the positive
area on a thermodynamic diagram. Units are Joules per kilogram. Larger
values are indicative of greater instability and the possibility of
stronger convective activity, including thunderstorms. Values around or
greater than 1000 suggest the possibility of severe weather should
convective activity develop.
CIN (Convective Inhibition) - An integrated measure of the amount of energy
needed to initiate convective activity, also known as the negative area on
a thermodynamic diagram. Units are Joules per kilogram. The more negative
this number, the more energy is required to initiate convection. This
inhibitive energy can be overcome through surface heating, cooling aloft,
lifting mechanisms (orographic, frontal, gravity waves, etc.)
Convective Condensation Level - The height to which an air parcel possessing the
average saturation mixing ratio in the lowest 4000 feet of the airmass,
if heated sufficiently from below, will rise dry adiabatically until it
just becomes saturated. It estimates the base of cumulus clouds that are
produced by surface heating only.
Convection Temperature (ConvectionT) - The surface temperature required to make
the airmass dry adiabatic up to the given level. It can be considered a
"trigger temperature" for that level.
Freezing Level - The height where the temperature is zero degrees Celsius.
Height of Stable Layer - The height (between 12,000 and 18,000 feet above
mean sea level) where the smallest lapse rate exists. The location and
existence of this feature is important in the generation of mountain
waves.
K Index - A measure of stability which combines the temperature difference
between approximately 5,000 and 18,000 feet above the surface, the amount
of moisture at approximately 5,000 feet above the surface, and a measure
of the dryness at approximately 10,000 feet above the surface. Larger
positive numbers indicate more instability and a greater likelihood of
thunderstorm development. One interpretation of K index values regarding
soaring in the western United States is given in WMO Technical Note 158
and is reproduced in the following table:
below -10 no or weak thermals
-10 to 5 dry thermals or 1/8 cumulus with moderate thermals
5 to 15 good soaring conditions
15 to 20 good soaring conditions with occasional showers
20 to 30 excellent soaring conditions, but increasing
probability of showers and thunderstorms
above 30 more than 60 percent probability of thunderstorms
Lapse Rate - The change with height of the temperature. Negative values indicate
inversions.
Lifted Condensation Level - The height to which an air parcel possessing the
average dew point in the lowest 4000 feet of the airmass and the forecast
maximum temperature must be lifted dry adiabatically to attain saturation.
Lifted Index (LI) - The difference between the environmental temperature at a
level approximately 18,000 feet above the surface and the temperature of
an air parcel lifted dry adiabatically from the surface to its lifted
condensation level and then pseudoadiabatically thereafter to this same
level. The parcel`s initial temperature is the forecast maximum
temperature and its dew point is the average dew point in the lowest 4000
feet of the airmass. Negative values are indicative of instability with
positive values showing stable conditions.
Lift Rate - An experimental estimate of the strength of thermals. It is
computed the same way as the maximum rate of lift but uses the actual
level rather than the maximum height of thermals in the calculation.
Also, none of the empirical adjustments based on cloudiness and K-index
are applied to these calculations.
Maximum Height of Thermals - The height where the dry adiabat through the
forecast maximum temperature intersects the environmental temperature.
Maximum Rate of Lift - An estimate of the maximum strength of thermals. It
is computed from an empirical formula which combines the expected maximum
height of thermals with the difference in the environmental temperatures
between the maximum height of thermals and the temperature 4,000 feet
above the ground. After this computation, further empirical adjustments
are made based on the value of the K-index and the amount and opacity of
middle and high level cloudiness expected between the time of trigger
temperature and the time of overdevelopment.
Middle/High Clouds - The amount and opacity of middle (altostratus, altocumulus)
or high (cirrus, cirrostratus, cirrocumulus) clouds. Broken means that
between 60% and 90% of the sky is covered by the cloud, with overcast
conditions occurring when more than 90% of the sky is covered by the cloud.
Thin implies that the clouds are predominantly transparent, meaning that
some sunlight is reaching the ground, in contrast to opaque which suggests
that little sunlight is reaching the ground.
Potential Height of Wave - The minimum of the following two heights:
1. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind direction changes by 30 degrees or more
2. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind speed no longer increases with height
PVA/NVA - Positive vorticity advection (PVA)/negative vorticity advection (NVA)
on the 500 millibar isobaric surface (approximately 18,000 feet above mean
sea level). Weak PVA has been shown to assist in mountain wave soaring.
Soaring Window - The time between the time the trigger temperature is reached
and the time of overdevelopment.
Thermal Index - The difference between the environmental temperature and the
temperature at a particular level determined by following the dry adiabat
through the forecast maximum temperature up to that level. Negative values
are indicative of thermal lift.
Thermal Soaring Index - An adjective rating (for sailplanes) based on the
computed maximum rate of lift, and the wind speed and middle and high
cloud cover expected during the soaring window (the time of the trigger
temperature and the time of overdevelopment) according to the following:
Maximum rate of lift Adjective Rating
>= 800 fpm Excellent
>= 400 and < 800 fpm Good
>= 200 and < 400 fpm Fair
< 200 fpm Poor
Time of Overdevelopment - The time one or more of the following phenomena,
which essentially shut off thermal lift, is expected to occur:
1. formation of broken to overcast convective cloud cover
2. formation of scattered to numerous downbursts
3. initiation of widespread precipitation
Time of Trigger Temperature - The time the surface temperature is expected to
reach the trigger temperature.
Trigger Temperature - The surface temperature required to make the first 4000
feet of the atmosphere dry adiabatic.
Wave Soaring Index - An empirical, adjective rating (for sailplanes) which
attempts to combine a variety of phenomena important in mountain wave
soaring into a single index number. Objective points are assigned to
these phenomena: wind speed and direction at 14,000 ft MSL, the static
stability in the 12,000-18,000 ft MSL layer, the wind speed gradient above
the stable layer, jet stream location and frontal and upper trough
movements.
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